How is interstitial cystitis diagnosed beyond symptom assessment?

Diagnosing Interstitial Cystitis Beyond Symptoms

The diagnosis of interstitial cystitis/bladder pain syndrome is primarily clinical and does not require cystoscopy or urodynamics in uncomplicated cases—diagnosis relies on careful history, physical examination, basic laboratory testing to exclude other conditions, and baseline symptom documentation using validated tools. 1, 2

Essential Laboratory Testing

The following tests are mandatory to establish the diagnosis:

• Urinalysis and urine culture must be performed to document negative cultures and exclude urinary tract infections 1, 2
• Urine cytology should be obtained if the patient has a smoking history or unevaluated microhematuria, given the risk of bladder cancer 1, 2
• Urine culture may be indicated even with negative urinalysis to detect lower bacterial levels that are clinically significant but not identifiable on dipstick or microscopy 1
• The potassium sensitivity test should NOT be performed as it lacks both specificity and sensitivity to change clinical decision-making 1, 2

Physical Examination Requirements

Beyond routine examination, specific assessments are necessary:

• Brief neurological examination to rule out occult neurologic problems that could explain symptoms 1, 2
• Evaluation for incomplete bladder emptying to exclude occult urinary retention 1, 2
• Assessment for dyspareunia in women and ejaculatory pain in men 1

Baseline Symptom Documentation

Validated measurement tools must be used to establish baseline values for monitoring treatment response:

• At minimum, a one-day voiding log to establish the presence of low-volume frequency voiding pattern characteristic of IC/BPS 1, 2
• Very low voiding frequencies or high voided volumes should prompt search for an alternate diagnosis 1
• Pain assessment using validated instruments: Genitourinary Pain Index (GUPI), Interstitial Cystitis Symptom Index (ICSI), or Visual Analog Scale (VAS) 1, 2
• Documentation of number of voids per day, sensation of constant urge to void, and location/character/severity of pain, pressure, or discomfort 1

When Cystoscopy IS Indicated

Cystoscopy is not routine but should be performed in specific circumstances:

• When Hunner lesions are suspected—this is the only reliable way to diagnose their presence, and early diagnosis is recommended without requiring patients to fail other treatments first 1, 2
• When the diagnosis is in doubt 1, 2
• To exclude bladder cancer, bladder stones, or intravesical foreign bodies when clinically suspected 1, 2
• In patients with unevaluated hematuria or tobacco exposure 1
• Cystoscopy for every IC/BPS patient is NOT advisable since the benefits/risks ratio is unfavorable, particularly for younger patients who have much lower prevalence of Hunner lesions 1

When Urodynamics ARE NOT Indicated

• There are no agreed-upon urodynamic criteria diagnostic for IC/BPS 1
• Urodynamics are not recommended for routine clinical use to establish an IC/BPS diagnosis 1, 2
• Urodynamic evaluation may be useful only when suspecting outlet obstruction in either sex, poor detrusor contractility, or other conditions explaining refractoriness to behavioral or medical therapies 1, 2

Critical Diagnostic Timeline

• Symptoms must be present for at least 6 weeks with documented negative urine cultures before diagnosis can be made 1, 2, 3
• This timeline allows for earlier treatment initiation compared to definitions requiring longer symptom durations 4

Common Diagnostic Pitfalls to Avoid

• Do not use research or clinical trial definitions (such as NIDDK criteria) in clinical practice—these are not appropriate outside of clinical trials and lead to underdiagnosis in 60% of patients 1, 4
• Do not treat with antibiotics when no infection is present, as this leads to antibiotic resistance and disruption of protective flora 4
• Do not perform cystoscopy routinely on all patients, especially younger patients with low risk of Hunner lesions 1
• Do not rely on cystoscopic glomerulations as diagnostic—there are no agreed-upon cystoscopic findings diagnostic for IC/BPS except Hunner lesions 1